This invention relates to advanced materials technology and especially to metallic glasses.
Metallic glasses, a class of amorphous alloys made by rapid solidification, have been studied quite extensively for almost thirty years. It has been recognized for a long time that metallic glasses are usually very strong and ductile, and exhibit high corrosion resistance relative to crystalline alloys with the same compositions.
Discussion of mechanical applications of metallic glasses can be found in "Amorphous Metallic Alloys", edited by F. E. Luborsky (Butterworths, Boston, 1983). Chief applications are in high-strength composites and reinforced materials. For many cases, it is desirable to apply high-strength low-density metallic alloys, such as metallic glasses based on aluminum. To date, attempts to produce ductile and/or thermally stable glassy aluminum alloys have failed.
The prior art has resulted in failures in applying high-strength low-density materials and producing ductile, strong, and/or thermally stable glassy aluminum alloys.
A preferred metallic glass aluminum based alloy has the formula Al.sub.85-90 (X,Z).sub.15-10 where X=Fe, Co, Ni, Rh and Z=rare earths, Hf and Y. The alloys are formed by arc-melting the elements in an argon atmosphere and forming the melt in a helium atmosphere and rapidly cooling the alloy to produce a single-phase amorphous aluminum rich alloy with high flexibility and high strength.
The preferred alloy has the formula Al.sub.90, Fe.sub.5, Ce.sub.5 having a tensile fracture strength of 940 MPa.
One alloy the invention has the formula Al.sub.87 Fe.sub.8.7 Gd.sub.4.3, and has a tensile fracture strength which exceeds 800 MPa.
Another preferred alloy of the invention has the formula Al.sub.87 Ni.sub.8.7 Y.sub.4.3 and has a tensile fracture strength of greater than 800 MPa.
Preferred alloys have the formula Al.sub.87-90 (a.sub.1-x b.sub.x) .sub.10-13, where 0.3&lt;X&lt;0.7; where a=Fe; and where b=Y, La, Ce, Sm, Gd, Lu, Hf.
Preferably the alloy is prepared with a formula Al.sub.87 Fe.sub.8.7 b.sub.4.3.
The preferred method for forming a ductile strong thermally stable glassy aluminum alloy comprises arc-melting nominal amounts of elements in the formula Al.sub.87-90 (a.sub.1-x b.sub.x).sub.10-13, where a=Fe, Co, Ni, Rh and b=rare earths Hf, Y.